A pressure vessel is a closed vessel that can withstand pressure. Pressure vessels are extremely versatile and have an important position and role in many sectors such as industry, civil, military, and scientific research. Among them, pressure vessels used most in the chemical industry and petrochemical industry, and only used in the petrochemical industry account for about 50% of the total number of pressure vessels. Pressure vessels are used in the chemical and petrochemical industries, mainly for heat transfer, mass transfer, reaction and other processes, as well as storage and transportation of pressurized gas or liquefied gas; they are also widely used in other industrial and civil fields, such as air. compressor. All kinds of special compressors and auxiliary compressors for refrigeration compressors (coolers, buffers, oil-water separators, gas storage tanks, evaporators, liquid refrigerants, etc.) are all pressure vessels.